OMEMO is an extension to the Extensible Messaging and Presence Protocol (XMPP/Jabber) for multi-client end-to-end encryption developed by Andreas Straub. According to Straub, OMEMO uses the Double Ratchet Algorithm 'to provide multi-end to multi-end encryption, allowing messages to be synchronized securely across multiple clients, even if some of them are offline'. The name 'OMEMO' is a recursive acronym for 'OMEMO Multi-End Message and Object Encryption'. It is an open standard based on the Double Ratchet Algorithm and the Personal Eventing Protocol (PEP, XEP-0163). OMEMO offers future and forward secrecy and deniability with message synchronization and offline delivery.